1. Field of the Invention
The present invention relates to an electrophotographic machine, and, more particularly, to a method of minimizing a delay in printing a first page in an electrophotographic machine.
2. Description of the Related Art
On laser printers and copiers with a rotating mirror and laser, time to first page can be of critical importance. A laser printer typically has a polygon mirror that, during printing, rotates at a constant angular velocity. Time to first page is a function of paper path length, image/media velocity and warm-up time of the polygon mirror. Typically, warm-up time involves waiting until the mirror is rotating at a specified velocity. Prior to printing, the polygon mirror accelerates from 0 rpm to some terminal rate of angular velocity.
In order to minimize time to first page, some processes that cannot be completed before the polygon mirror has achieved constant speed must nevertheless be started before the polygon mirror has achieved constant speed. Such concurrent processes may include bias voltage stabilization, performing an erase cycle on a photoconductive drum, and performing a paper pick operation. Traditionally, before the processes are commenced, the angular velocity of the mirror increases rapidly and then a long delay time is allowed in order to guarantee that the velocity is exactly equal to the desired rate before the concurrent processes are complete. Imaging on the photoconductor cannot begin until the angular velocity exactly matches the terminal rate. This typically affects the xe2x80x9ctime to first pagexe2x80x9d, i.e., the time the user must wait to get the first printed page output from the printer.
What is needed in the art is a method of minimizing the delay in time to first page associated with mirror motor warm-up time.
The present invention provides a method of predicting an amount of time needed for polygon mirror warm-up.
The invention comprises, in one form thereof, a method of activating an electrophotographic machine. At least one condition of the electrophotographic machine is determined. Power is applied to a polygon mirror. A time period required for the polygon mirror to accelerate from a stationary condition to a target rotational velocity is measured. The measured time period and data associated with the at least one condition are stored in a memory device. The polygon mirror is decelerated back to the stationary condition. Power is reapplied to the polygon mirror at a point in time. The measured time period and the data are used to determine when to begin at least one process in the electrophotographic machine relative to the point in time.
An advantage of the present invention is that the delay in time to first page associated with mirror motor warm-up is minimized.
Another advantage is that, with the reduced delay in time to first page, there is less wear on the printhead since the total time that the polygon mirror is rotating is reduced.
Yet another advantage is that adequate controls are provided to guarantee that printing does not begin too early, which could cause print defects.
A further advantage is that there is very little cost associated with implementing the present invention.